发表机构
University of Science and Technology of China; Hangzhou Institute for Advanced Study, UCAS; Peng Huanwu Center for Fundamental Theory; Ningbo University（中国科学技术大学; 中国科学院大学杭州高等研究院; 彭桓武理论物理中心; 宁波大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文构造Kerr-Bertotti-Robinson时空的解析延拓，揭示其违反弱宇宙监督的奇点链，并证明轴对称扰动存在虚频增长模，支持黑洞炸弹机制。
AI 中文摘要
Kerr-Bertotti-Robinson时空的$r=\infty$表面并非真正的边界。我们构造了其自然的解析延拓，并证明一个KBR区域的$r=+\infty$与相邻区域的$r=-\infty$光滑连接。重复延拓产生由类虫洞桥连接的区域无限链，并暴露出相邻的环状奇点，其间没有视界，这违反了弱宇宙监督猜想。随后，我们在双宇宙散射段上研究无质量标量场以探测时空的稳定性。对于轴对称扰动，我们解析地证明了每个$\ell$都存在纯虚增长的拟正规模，并将其起源追溯到破坏时序的区域。在$(\ell,m)=(2,2)$扇区中，当旋转足够大且磁场足够小时会出现不稳定分支。它们的临界实模满足精确的视界通量平衡，支持黑洞炸弹解释，即超辐射提取被双势垒内的捕获所放大。同一空腔还支持弱阻尼模族，并可能产生类似回波的响应。
英文摘要
The surface $r=\infty$ of the Kerr-Bertotti-Robinson spacetime is not a genuine boundary. We construct its natural analytic extension and show that $r=+\infty$ of one KBR region is smoothly connected to $r=-\infty$ of a neighboring one. Repeated continuation produces an infinite chain of regions connected by wormhole-like bridges and exposes the neighboring ring singularity without an intervening horizon, which violates the weak cosmic censorship conjecture. We then study a test massless scalar field on a two-universe scattering segment to probe the stability of the spacetime. For axisymmetric perturbations, we analytically establish purely imaginary growing quasinormal modes for every $\ell$ and trace their origin to the chronology-violating region. In the $(\ell,m)=(2,2)$ sector, unstable branches occur for sufficiently large rotation and sufficiently small magnetic field. Their marginal real modes obey an exact horizon-flux balance, supporting a black-hole-bomb interpretation in which superradiant extraction is amplified by trapping within the double-barrier potential. The same cavity also supports families of weakly damped modes and may produce echo-like responses.
Commentsrevtex4, 28 pages, 12 figures, 1 table, Companion to arXiv:2608.19136
